The majority of existing e-commerce design guidelines has been derived by conducting heuristic evaluations, without reporting the involvement of the users themselves. This research provides clarification on a number of existing web design guidelines for e-commerce sites based on empirical studies with users. Four studies were conducted and each study focused on a specific set of design guidelines as found in the literature. A combined qualitative and quantitative approach has been used, including a state-of-the-art technique, eye tracking. The eye movement data were complemented by user-profile data elicited through background questionnaires and user-perception data as captured through semi-structured interviews. The first study investigated users’ initial impressions of homepages of e-commerce sites. The second study examined users’ adaptability to persistent or varied placement of design elements. The third and fourth studies explored the effect of the presentation format of e-commerce web pages: the first in terms of the proportion of images, and the second in terms of how key icons related to an e-commerce transaction were presented. On the whole, the results of the studies corroborated existing design guidelines, but they also identified potential refinements. The thesis contributes both methodologically and empirically to Human-Computer Interaction. The combined methodological approach enables insight into the user experience that spans behavioural aspects such as visual search behaviour and visual search performance data, and subjective aspects such as user expectations and preferences. The empirical outcomes amplify the design guidelines from a user’s perspective.